A photocathode structure, which can include an alkali halide, has a protective film on an exterior surface of the photocathode structure. The protective film includes ruthenium. This protective film can be, for example, ruthenium or an alloy of ruthenium and platinum. The protective film can have a thickness from 1 nm to 20 nm. The photocathode structure can be used in an electron beam tool like a scanning electron microscope.

Electron source designs are disclosed. The emitter structure, which may be silicon, has a layer on it. The layer may be graphene or a photoemissive material, such as an alkali halide. An additional layer between the emitter structure and the layer or a protective layer on the layer can be included. Methods of operation and methods of manufacturing also are disclosed.

A photocathode can include a body fabricated of a wide bandgap semiconductor material, a metal layer, and an alkali halide photocathode emitter. The body may have a thickness of less than 100 nm and the alkali halide photocathode may have a thickness less than 10 nm. The photocathode can be illuminated with a dual wavelength scheme.

A flat top laser beam is used to generate an electron beam with a photocathode that can include an alkali halide. The flat top profile can be generated using an optical array. The laser beam can be split into multiple laser beams or beamlets, each of which can have the flat top profile. A phosphor screen can be imaged to determine space charge effects or electron energy of the electron beam.

An electron emission tube includes a housing in which an internal space is provided and which keeps the internal space in vacuum, an electron source that is arranged on a first end side in one direction of the housing and that generates an electron, a gate valve that is arranged on a second end side in the one direction of the housing and that can switch the second end side between an open state and a blocked state, and a partition part that is placed between the electron source and the gate valve and that divides the internal space into a first region including the electron source and a second region including the gate valve. The partition part includes an electron-permeable membrane that transmits an electron.

Provided is a photocathode kit that does not require adjustment of the distance between a photocathode film and a lens focusing on the photocathode film when the photocathode and the lens are installed inside an electron gun. The photocathode kit includes: a photocathode including a substrate in which a photocathode film is formed on a first surface; a lens; and a holder that holds the substrate and the lens, and the holder has a retaining member that retains the photocathode film and the lens to be spaced apart by a predetermined distance, and a first communication path that communicates between inside of the holder and outside of the holder.

A system for generating an electron beam array, comprising a light source, a first substrate having a plurality of plasmonic lenses mounted thereon, the plasmonic lenses configured to received light from the light source and produce an electron emission, and a plurality of electrostatic microlenses configured to focus the electron emissions into a beam for focusing on a wafer substrate. A light source modulator and digital micro mirror may be included which captures light from the light source and projects light beamlets on the plasmonic lenses.

A probe assembly for analyzing a test device that includes a housing with an electron source disposed therein for emitting primary electrons. A photon source is positioned to emit photons that strike the electron source such that when the photons strike the electron source, the electron source emits the primary electrons. Detection circuitry is provided that is configured to detect secondary electrons emitted from a test device of a test assembly and to form an excitation waveform.

An inspection device for inspecting a surface of an inspection object using a beam includes a beam generator capable of generating one of either charge particles or an electromagnetic wave as a beam, a primary optical system capable of guiding and irradiating the beam to the inspection object supported within a working chamber, a secondary optical system capable of including a first movable numerical aperture and a first detector which detects secondary charge particles generated from the inspection object, the secondary charge particles passing through the first movable numerical aperture, an image processing system capable of forming an image based on the secondary charge particles detected by the first detector; and a second detector arranged between the first movable numerical aperture and the first detector and which detects a location and shape at a cross over location of the secondary charge particles generated from the inspection object.

An object is to provide an electron gun that makes it possible to verify whether or not an electron beam emitted form a photocathode is misaligned from a designed emission center axis. The object can be achieved by an electron gun including: a light source; a photocathode; and an anode. The electron gun includes an intermediate electrode arranged between the photocathode and the anode, an electron beam shielding member configured to block a part of an electron beam, a measurement unit configured to measure an intensity of an electron beam blocked by the electron beam shielding member, and an electron beam emission direction deflector arranged between the anode and the electron beam shielding member and configured to change a position where an electron beam that passed through the anode reaches the electron beam shielding member. The intermediate electrode has an electron beam passage hole and a drift space.